Please make a right click on the virtual machine as listed by Hyper-V Manager, make a click on "Settings...". On the left panel make a click on Security. and on the right side of the window uncheck a feature named "Enable secure boot". To do that you need to power off the VM first.
Make sure you have created an external virtual switch on Virtual Switch Manager, and make sure the Network Adapter of the VM is assigned to that switch. Make sure the IP address of the VM is compatible with the IP of your computer. Make sure firewall settings or security software on the VM and in your computer allow RDP, Ping connections.
Try that. Hope it helps.